The use of small-scale work vehicles—vehicles such as animal-drawn forecarts, all terrain vehicles (“ATVs”) and small-scale tractors—is greatly increasing. Generally however, these smaller work vehicles cannot accomplish the things that a large-scale farm tractor can, at least not with the same degree of speed or quality. Because of economics and otherwise, there is a desire for a tool which would allow these smaller work vehicles to do much of what larger-scale vehicles can.
Three point hitches are used by a variety of work vehicles—such as animal-drawn forecarts, ATVs, and wheeled or tracked large and small-scale tractors—to attach an implement to the work vehicle and to raise or lower the implement relative to the work vehicle to and from a field-use position. By their nature, three point hitches provide such a work vehicle with increased flexibility to perform a number of tasks which otherwise would require a variety of more specialized single function vehicles.
Three point hitches generally are comprised of two spaced lower links and a top link above and between the two lower links. Each of the top link and lower links has an end configured for engaging and attaching the implement to the work vehicle. To lift the implement, the three point hitch generally includes one or more hydraulic cylinders, which directly or indirectly pivot the lower links to lower and raise the implement. As the implement is raised and lowered, the top link typically stabilizes the implement and maintains the implement in a desired orientation relative to the work vehicle.
Three point hitches are generally either rear/front mounted directly onto the work vehicle, or rear mounted on an attached trailer. There are drawbacks with either of these methods which generally force smaller work vehicles to hitch to and manipulate smaller, and typically much less useful and/or efficient, implements.
A hitch which is directly attached to the work vehicle, either in front or in back, presents several disadvantages. Such an attached hitch (i) increases the length of the work vehicle thereby decreasing mobility and sight-lines and (ii) imposes a directly opposing force on the work vehicle thereby limiting the scale and weight which can be carried in the hitched implement. Additionally, front-mounted direct hitches move the implement laterally as the work vehicle is being turned—an undesirable effect especially when the hitched implement is engaged in the ground.
When pulled by a relatively smaller draft vehicle, trailer-attached hitches are generally relegated to carrying relatively smaller implements. Obviously, the scale of the trailer must reduce in accordance with the scale of the draft vehicle. Generally however, as the trailer becomes smaller and lighter, the weight of the hitched implement and corresponding load typically reduces at an even faster rate for a number of reasons. With the design of the typical three point hitch, the top link either remains stationary relative to the two lower links or moves in conjunction with the two lower links. Either way, the fulcrum of the load remains fixed back of the trailer's axle, thereby limiting the allowable weight of the implement. A heavier implement puts more direct downward force on the back of the trailer, thereby forcing the tongue of the trailer up and comprising the coupling with the work vehicle. Additionally, the movement of a typical three point hitch limits the consistency of position with which the operator can return the attached implement. Moreover, typical three point hitch trailers, like any standard-steering trailer, have a tendency to jackknife (i.e. the point of attachment between the trailer and the draft vehicle becomes an uncontrolled articulation) and are exceedingly unstable, especially on varied terrain—a tendency which grows (along with the severity-of-result) with the weight of the hitched implement and corresponding load. The tongue, which connects the trailer to the draft vehicle, needs to be long enough to avoid interference between the two when turning.
Synchronizing the steering (the inapposite angular movement of the trailer axle relative to that of the draft vehicle) and controlling the articulation (by moving the pivot point from the typical point of attachment at the tongue to the recessed mid-carriage pivot point and allowing the nature of synchronization to mechanically control the degree of articulation) of the trailer helps address the stability of the vehicle combination especially over varied terrain. Synchronizing the steering also permit's the tongue to be shortened; thereby increasing the mobility of the vehicle combination.
The uncontrolled articulation of the typical vehicle combination can present problems. As anyone who has tried can attest, backing up a trailing vehicle or vehicle combination is very hard. There is an increased tendency to jackknife and it is difficult to maneuver the vehicle combination to the desired location.
Therefore, there is a growing desire for an articulating trailer whereby the articulation is controlled via the synchronized steering of the trailer wheels and contains a hitch that may pull the fulcrum toward the trailer's weight bearing axles(s) when handling implements. Without limitation, an immediate example illustrates. For various reasons, many farmers are switching to the use of large round bales of hay and straw from the more familiar smaller rectangle bales. The former can weigh up to two thousand pounds while the latter typically weighs forty to one hundred pounds. Because of the reasons briefly described above, small-scale work vehicles cannot easily handle the larger round bales—and they certainly cannot do so in varied or wooded terrain. The desired combination of synchronized steering with mechanically-controlled articulation along with a fulcrum-moving hitch system allows smaller work vehicles to safely lift, handle and move heavy implements and loads such as these large round bales, and thus do work, typically done by much heavier work vehicles.